RECOVERY OF EDTA FROM WASTE PLATING LIQUID

摘要

PURPOSE:To recover H4Y with high efficiency, by washing a part of a separated free acid (hereinafter referred to as H4Y) with an unsaturated H4Y solution and precipitating the obtained substance as a seed crystal. CONSTITUTION:A part of a separated free acid (hereinafter referred to as H4Y) crystal is washed with an unsaturated H4Y solution and the obtained substance is added to a waste liquid containing ethylenediaminetetraacetic acid (hereinafter referred to as EDTA) to be precipitated as a seed crystal. Then, the H4Y crystal grown into a predetermined particle size is subjected to solid-liquid separation. By this method, the particle size of the crystal can be made large, and washing and dehydration become easy and the H4Y crystal can be recovered with high efficiency.